Bag

ABSTRACT

A bag has side walls and a flat bottom having lateral folds and corner folds. An insert of thermally insulating material is located in the flat bottom extending underneath the corner folds and having folded lateral portions which extend beyond the lateral folds but not beneath the corner folds. The folded portions of the bottom are bonded, adhesively or by heat-bonding if the bottom is of requisite heat-bondable material.

llnited States Patent 1191' Erk et al. 1 May 22, 1973 BAG [56]References Cited [75] Inventors: Amir Erk, Grossdornberg; Ottomar UNITEDSTATES PATENTS Tiessmaun; Klaus Schirrich, both of 2,359,190 9/1944Avery etal. ..229/5s Bl all of Germany 2,420,212 5 1947 Volksdorf 1..229/5s x 2,853,225 9/1958 Bauer ..229/58 [73] Assgnee- Kmk Belefeld'3,514,033 5 1970 Goodwin ..229/58 x Germany [22] Filed; M 26, 1971Primary Examiner-Davis T. Moorhead Attorney-Michael S. Striker [21]Appl. No.: 145,085

[57] ABSTRACT Foreign Application Primity Data A bag has side walls anda flat bottom having lateral May 29 1970 Germany "P 20 26 3303 folds andcorner folds. An insert of thermally insulating material is, located inthe flat bottom extending underneath the corner folds and havin foldedlateral 52 U.S. Cl ..229 58 3 E Int Cl B65d 33100 portions which extendbeyond the lateral folds but not [58] Fieid 229/58 55 beneath the cornerfolds. The folded portions of the bottom are bonded, adhesively or byheat-bonding if the bottom is of requisite heat-bendable material.

10 Claims, 5 Drawing Figures Patented May 22, 1973 Fig.

/n vem0r A, n K mronn Texsrnvu BAG BACKGROUND OF THE INVENTION Thepresent invention relates generally to bags, and more particularly toflat-bottom bags.

Flat-bottom bags, also known as cross-bottom or block-bottom bags, areknown which consist at least in part of heat-bondable material so that,when the necessary folds are carried out, the bag is closed at thebottom by sealing it under the influence of heat. The difficulty withthe existing prior art is that when sealing is carried out, thoseportions of the side wall which overlie the bottom interiorly of the bagin contact therewith-while the bag is in the folded condition in whichthe sealing takes place rather than in unfolded condition in which noportions of the side wall would be in contact with the bottom-frequentlyare also sealed to the bottom. Such a bag of course must be discardedbecause it is not'usable.

It is already known in cross-bottom or block-bottom bags composed ofseveral layers or plies of paper, to in corporate into the bottom areinforcing strip which extends under the corner folds and beyond thelateral fold lines of the bottom. The rectangular reinforcing strip hasthe dual function of serving for reinforcing purposes and also to sealthe bottom in such a manner that subsequently introduced contents cannotenter between the individual paper layers of the bottom of the bag.

SUMMARY OF THE INVENTION It is a general object of the present inventionto promeans is composed at least in part of heat-bonded material andcomprises lateral folds and corner folds. An insert of thermallyinsulating material is accommodated in the flat bottom means extendingunderneath the corner folds and having folded lateral portions whichextend beyond the lateral folds but not underneath the corner folds.

This insert prevents excessive transfer of thermal energy in the regionof the bonding linesthat is heatsealing lines-where the folded-togetherportions of the bottom are adhered in order to close the bottom, that isthe lower end of the bag. These heat-sealing lines on the one handconnect the corner folds with the lateral folds, and on the other handconnect the lateral folds with one another. By the provision of theinsert any adhering during such sealing operations of the bottom toportions of the side wall which are in contact with the bottom isavoided.

Furthermore, the provision of the lateral portions on the insert whichextend under the lateral folds but not under the corner folds, meansthat the insert is provided with recesses in the region of its cornersand, because of this, the lateral folds of the bottom can be welded orbonded with the corner folds over the entire width of the bottom withoutinterference by the insert. The foldable portions of the insert providethe advantage that they reduce the necessity for a precise positioningof the insert with reference to the bottom before the latter is foldedand bonded, so that the manufacture of the bag is greatly simplified.

In so far as the material for the insert is concerned, I have found thatstiff paper or cardboard is entirely adequate for providing the desiredretardation of thermalenergy transfer. Of course, the insert at the sametime constitutes a reinforcement for the bottom which is highlydesirable, particularly in cases where the bag including the bottom isof synthetic plastic material which is often strongly stressed in use.

The insert can be adhesively or otherwise secured with those portions ofthe corner folds underneath which it extends; on the other hand, if itis provided on one side with a layer of heat-bondable material, such asa suitable synthetic plastic, the securing need not be adhesive but caninstead be by heat bonding, and in this case the connection can beestablished at the same time as the other portions of the bottom areheat-bonded to one another.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic viewillustrating the lower end including the bottom of a bag according tothe present invention, with the bottom partially folded;

FIG. 2 is the same view as FIG. 1 but illustrating the insulatingmaterial insert in place in the bottom of the bag;

FIG. 3 illustrates the embodiment of FIG. 2 with the bottom in finallyfolded and bonded condition;

FIG. 4 is a diagrammatic section on line IV-IV of FIG. 2; and

FIG. 5 is a diagrammatic section on line V--V of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail it will be seen that reference numeral 1 identifies in toto atubular component which is provided with the broken-line illustratedside wall gussets, so that it can be folded flat as illustrated. It isprovided with the customary block bottom which is shown in partiallyfolded condition in FIG. 1. Side folds 2 and 3 are illustrated, as wellas the corner folds 4 and 5. FIG. 2 shows how an insulating material(thermally insulating) insert 6 is placed into the partially foldedbottom, through the openings 7 and 8. FIGS. 2 and 3 show clearly thatthe insert 6 has such a width that it extends at opposite sidesunderneath the corner folds 4 and 5. It is further provided, in theillustrated embodiment, with adhesive strips 9 and 10 by means of whichit is adhesively connected with the overlying portions of the cornerfolds 4 and 5.

In addition, the insert 6 is provided with lateral projections orportions 6a which extend beyond the fold lines 11 and 12 of the lateralfolds 2 and 3 and which can thus be folded together with the latter. Theportions 6a are recessed at the corners so that they do not extendbeneath the corner folds 4 and 5. FIGS. 2 and 3 show clearly that thesecorner recesses 6b of the insert 6 assure a bonding of the lateral folds2 and 3 with the corner folds 4 and 5 over the entire width of thebottom.

Once the insert 6 has been positioned as illustrated in FIG. 2, thebottom is folded to the position illustrated in FIG. 3, and thereuponthe lateral folds 2 and 3 are connected with the corner folds 4 and 5along bonding lines 13 and 14, as by heat bonding if the material is ofrequisite type, and the lateral folds 2 and 3 are connected with oneanother by a bonding line 15. In FIG. 3 the bonding lines 13 and 14 areabove the adhesive strips 9 and 10.

It is pointed out, however, that the adhesive strips 9 and could beomitted, and that instead the insert 6 could be provided with a layer ofheat-bendable material (thermoplastic material), for instance of thesame type as the-bag itself, in which case they can then be heat-bondedwith the overlying portions of the corner folds, 4 and S at the sametime as the bonding steps discussed above with respect to FIG. 3 arecarried out. The sections of FIGS. 4 and 5 show details of FIGS. 2 and3, respectively. I

It is also pointed out that instead of the separate insert 6, forinstance of stiff paper or cardboard, the bag can be provided at leastin the region of the subsequently provided bonded lines or bonding seamswith a layer or coating of an insulating material, for instance pigmentpaint, lacquer or the like which provides the desired thermallyinsulating function.

It will be understood that each of the elements described above, or twoor more together, may also find auseful application in other types ofapplications differing from the types described above.

While the invention has been illustrated and described as embodied in abag, it is not intended to be limited to the details shown, sincevarious modifications and structural changes can be made withoutdeparting in any way from the spirit of the present inventron.

7 Without further analysis, the foregoing will so fully reveal the gistof the present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A bag, comprising side wall means; flat bottom means at the lower endof said side wall means and comprised at least in part of heat-bondablematerial, said flat bottom means comprising lateral folds and cornerfolds; and thermally insulating means in said flat bottom means,extending underneath said corner folds and having lateral portions whichextend beyond said lateral folds and have corners provided with recesseslocated underneath said corner folds so that no part of said lateralportions extends underneath said corner folds.

2. A bag as defined in claim 1, wherein said insulating means consistsat least predominantly of relatively stiff paper.

3. A bag as defined in claim l,'wherein said insulating means consistsat least predominantly of cardboard.

4. A bag as defined in claim 1, wherein said insulating means is aninsert having two major sides, one of which is provided with a layer ofheat-bondable material.

5. A bag as defined in claim 1, wherein said insulating means is aninsert member bonded to said corner folds underneath which it extends.

6.. A bag as defined in claim 5, wherein said insert member isheat-bonded to said corner folds.

7. A bag as defined in claim 5, wherein said insert member is adhesivelybonded to said corner folds.

8. A bag as defined in claim 1, said flat bottom means having aplurality of bonding seams and wherein said flat bottom means isprovided with a coating of thermally insulating material in the regionof said bonding seams and constituting said thermally insulating means.

9. A bag as defined in claim 8, wherein said insulating material is athermally insulating lacquer.

10. A bag as defined in claim 8, wherein said insulating material is apigment paint.

1. A bag, comprising side wall means; flat bottom means at the lower endof said side wall means and comprised at least in part of heat-bondablematerial, said flat bottom means comprising lateral folds and cornerfolds; and thermally insulating means in said flat bottom means,extending underneath said corner folds and having lateral portions whichextend beyond said lateral folds and have corners provided with recesseslocated underneath said corner folds so that no part of said lateralportions extends underneath said corner folds.
 2. A bag as defined inclaim 1, wherein said insulating means consists at least predominantlyof relatively stiff paper.
 3. A bag as defined in claim 1, wherein saidinsulating means consists at least predominantly of cardboard.
 4. A bagas defined in claim 1, wherein said insulating means is an insert havingtwo major sides, one of which is provided with a layer of heat-bondablematerial.
 5. A bag as defined in claim 1, wherein said insulating meansis an insert member bonded to said corner folds underneath which itextends.
 6. A bag as defined in claim 5, wherein said insert member isheat-bonded to said corner folds.
 7. A bag as defined in claim 5,wherein said insert member is adhesively bonded to said corner folds. 8.A bag as defined in claim 1, said flat bottom means having a pluralityof bonding seams and wherein said flat bottom means is provided with acoating of thermally insulating material in the region of said bondingseams and constituting said thermally insulating means.
 9. A bag asdefined in claim 8, wherein said insulating material is a thermallyinsulating lacquer.
 10. A bag as defined in claim 8, wherein saIdinsulating material is a pigment paint.